The present invention relates generally to input pointing devices, more particularly, it relates to compact low profile input device suitable for use in handheld devices for moving a cursor, scrolling, and navigation and selection of objects on a display.
Pointing devices have long been used with computers for facilitating user interaction with graphical user interfaces associated with computer operating systems by, for example, providing means for general navigation and selection of objects. Generally speaking, pointing devices are input devices that are used to move a cursor quickly and accurately to a desired position on a display. Dedicated pointing devices offer far greater utility for cursor movement than pressing the arrow keys on the keyboard, for example. Some of the most common pointing devices include mice, trackballs, touchpads, joysticks, and light pens. The mouse is the input device that is by far the most commonly used with computers. Typically, the mouse is an external device connected to the computer that translates user hand motion into signals that the computer understands to move the cursor in the desired direction on the screen. Similar in function, a trackball is an input devices that is a relatively large sphere that users rotate with their fingers to move the cursor. These have been particularly popular with CAD (Computer Aided Design) users for precision work but they often have a relatively high learning curve for the casual user.
Another type of pointing device that is widely used with computers are touchpads. Although, touchpads have been primarily used on laptops because they can be easily integrated into the unit, they have been becoming more popular for use with desktop computers as well. Cursor movement is performed by dragging the tip of the finger across the touchpad surface and tapping the surface to click on an object. Touchpad use also has a bit of learning curve since tactile feedback is lacking i.e. provides no analog force feedback to aid the user, especially when approaching the edges of the touchpad. Tactile feedback often aids the user in controlling the movement of the cursor, for example, by increasing or slowing the speed at which the cursor moves by pressing or moving a greater or lesser amount with the pointing device. Furthermore, the nature of touchpads requires a certain amount of surface area to move your finger around thus making them unsuitable for use in small handheld devices. In the case of touchscreens, where the user points to a location on the screen that is responsive to a pointing device such as a pen or stylus, this input technique also lacks tactile feedback and requires an external stylus which the user must carry around.
Joysticks are widely used in gaming applications where cursor movement is effected by moving the free end of the joystick about a pivoting end. Although joysticks present and intuitive way to move around the screen, they have the drawback of being relatively large (i.e. extended shaft and knob). This aspect makes them particularly unsuitable for use in compact environments such as laptops, not to mention smaller devices such as PDAs (Personal Digital Assistant) etc. Moreover, normal use of the joystick results in mechanical stress applied to soldering pads and rollers which decreases its reliability over time. Light pens are very intuitive and easy to use since one just points to a desired location on the screen for navigation or selection. However, the effectiveness of light pens is greatly dependent on the size of the screen and they become increasing more difficult to use with handheld devices with small screens, for example.
Although each of the described prior art pointing devices have their advantages in certain respects, they are not suitable for use in the new generation of compact handheld devices. Touchscreens have been successfully employed in these smaller devices but they suffer from the lack of tactile feedback and the inconvenience of using a stylus that must be tucked away in the device housing that adds bulk. It should be noted that the term handheld devices is used herein refers to portable devices such as personal digital assistants and wireless communicator devices such as the Nokia 9110 Communicator and its successors. Many of these devices are typically characterized in that the display, the keyboard, typically a QWERTY format keyboard which provides more convenient character input for the user, and the pointing device are integrated into a main unit as opposed to being separately attached. A significant attribute of handheld devices is that their small form factor makes them convenient, lightweight and easy to carry. This in turn places strict limits on the amount of space a pointing device can occupy.
A common feature of a cellular phone today is short messaging (SMS), wherein the user types a short textual message using the conventional keypad of the phone and then sends it to another cellular phone. As the short messaging and other applications typically related with interaction between users, such as electronic mail, are developed and become commonly used, the conventional keypad of the cellular phone may not fulfill the requirements of a user. One key factor is the ease and speed of typing a message. Some manufacturers have anticipated this and provided an additional separate keypad unit attachable to a cellular phone (such as the Ericsson Chatboard). These devices are preferably small and lightweight, yet providing an alphabetic keyboard with additional access keys for common functions, such as the aforementioned mail and SMS and also preferably a set of keys for moving the cursor. As the functions of cellular phones evolve, a need for a low profile device for moving the cursor is anticipated for also this kind of auxiliary units.
Cellular phones with conventional key or keypad arrangements such as is disclosed in USD423,515, or other types such as disclosed in USD415,770 are commonly used. The increasing use of additional functions and features of the cellular phone, such as games, internet access, calendar functions and such, may require the manufacturer of the cellular phone to incorporate a scrolling device into the device. One example of such device is disclosed in EP 901 262. This navigation key provides a rather compact construction for a relatively small device, allowing the user to e.g. scroll menus, select functions, etc. However, as the form of the roller key suggests, the roller key requires some space within the device and therefore is not preferred for a very low profile handheld device, especially not for a clamshell type of a device. Further, these navigation keys typically allow moving the cursor or selection to two directions only, i.e. up-down, right-left, and cannot therefore be effectively used for functions requiring free cursor movement.
U.S. Pat. No. 5,504,502 describes a pointing control device that is suitable for use on laptop computers. The device construction details a movable actuating member containing a magnet that is detected by magnetic reluctance detectors and where the member is returned to the center position by a spring. However, the construction has the drawback of being relatively complicated whereby the supporting structure and the spring must be constructed into the device housing. This makes the device less compact with respect to height and thus, although satisfactory for use in relatively larger laptop computers, it is less useful for relatively small handheld devices, particularly those employing a folding clamshell design. Moreover, the single magnet used in the described device produces a relatively weak magnetic field. Thus the reluctance detectors must be very sensitive thereby adding to the overall bulk of the construction. Also, because of the spring force the device is rather onerous in use on ones finger or thumb, whereby the user will easily find the device unsuitable for longer use.
FIG. 1 shows a handheld communicator type device that exemplifies the space layout constraints inherent in many small footprint devices. The device is comprised of a main unit 100 into which a plurality of keys 104 forming keyboard are integrated into surface 108 of main unit. For improved compactness, the device is constructed of a two piece folding clam shell design pivoting about hinge 116 which is comprised of the main unit 100 and an upper portion 118 containing a display 120. Due to the small footprint, there is very little space on surface 108 for a pointing device of the kind described above. To control cursor movement, a group of four arrow keys 112 are employed for movement in a corresponding direction of the arrow. The use of arrow keys, similar in function to those on a PC keyboard, works well as a space saving solution for rudimentary movement of the cursor. However, pushing arrow keys typically moves the cursor or scrolls the screen in discrete steps which do not provide the smooth and efficient movement provided by other pointing devices. Moreover, arrow keys do not provide the tactile feedback necessary to aid the user during navigation or scrolling.
In view of the foregoing disadvantages set forth above, it is an objective of the present invention to provide an input device and scrolling mechanism that is compact, efficient and provides suitable tactile feedback for effective use in small handheld devices.
Briefly described and in accordance with an embodiment and related features of the invention, there is provided an input device for moving a cursor on a display screen comprising:
a device housing;
a movable sliding member having a first ferromagnetic element attached thereto;
a second ferromagnetic element located in a fixed position relative to the first ferromagnetic element; and
at least two sensors for measuring the relative movement of the sliding member.
In a apparatus aspect there is provided an electronic device comprising a display screen for displaying a cursor during operation of the device, the electronic device is characterized in that the device includes an input device for moving a cursor on a display comprising:
a movable sliding member having a first ferromagnetic element attached thereto;
a second ferromagnetic element located in a fixed position relative to the first ferromagnetic element; and
at least two sensors for measuring the relative movement of the sliding member.
In a further input device aspect there is provided a sliding input device moving in discrete steps between a first fixed position and a second fixed position for selecting a function on a electronic device, the input device comprising:
a movable sliding member having a first magnet attached thereto;
a second magnet fixed in position at the first fixed position;
a third magnet fixed in position at the second fixed position a proximate distance from the first position;
a support layer for supporting the second magnet and the third magnet in their respective fixed positions; and
at least two sensors for detecting the position of the sliding member.
In a method aspect there is provided a method of moving a cursor on a display screen with an input device by sliding a slide element attached to a first magnet over a second magnet located in a fixed position, whereby by relative movement of the slide element is measured by at least two sensors and translated into movement of the cursor.